While these tutorials are typically meant to be visualized in serial, viskex also runs in parallel. To exemplify this, we will show a parallel case using ipyparallel.
First of all, we start a ipyparallel MPI cluster with 2 processes.
import ipyparallel as ipp
cluster = ipp.Cluster(engines="MPI", profile="mpi", n=2)
cluster.start_and_connect_sync()
Starting 2 engines with <class 'ipyparallel.cluster.launcher.MPIEngineSetLauncher'>
<ipyparallel.client.client.Client at 0x7fd678357b60>
The jupyter magic %%px will run the following cells on the ipyparallel cluster.
%%px
import firedrake # noqa: E402
import mpi4py.MPI # noqa: E402
%%px
import viskex # noqa: E402
To confirm that we are running in parallel, we can print the rank of the current process and the total number of processes.
%%px
comm_world = mpi4py.MPI.COMM_WORLD
print(f"rank = {comm_world.rank}, size = {comm_world.size}")
[stdout:1] rank = 1, size = 2
[stdout:0] rank = 0, size = 2
Generate a mesh on MPI_COMM_WORLD of the unit square by dividing each edge of the square in 6 segments.
%%px
square_world = firedrake.UnitSquareMesh(
6, 6, comm=comm_world, distribution_parameters={"partitioner_type": "simple"})
Plot the mesh defined on MPI_COMM_WORLD. Each rank will plot its local cells, and their neighbors (called halos in firedrake).
%%px
viskex.firedrake.plot_mesh(square_world)
[output:1]
[output:0]
For comparison, we can generate a similar mesh on MPI_COMM_SELF. Each rank will have its own copy of the whole mesh.
%%px
comm_self = mpi4py.MPI.COMM_SELF
square_self = firedrake.UnitSquareMesh(
6, 6, comm=comm_self, distribution_parameters={"partitioner_type": "simple"})
Plot the mesh defined on MPI_COMM_SELF. Each rank will produce a plot which is visually the same, since each rank has its own copy of the same mesh.
%%px
viskex.firedrake.plot_mesh(square_self)
[output:1]
[output:0]
We finally stop the ipyparallel cluster. Note that when running with Run -> Run all cells all interactive plots will be closed when the kernel executes this cell.
cluster.stop_cluster_sync()
Stopping controller
Controller stopped: {'exit_code': 0, 'pid': 4372, 'identifier': 'ipcontroller-1753899547-3hrl-4354'}
Stopping engine(s): 1753899548
Output for ipengine-1753899547-3hrl-1753899548-4354: 2025-07-30 19:19:08.589 [IPEngine] Loading connection info from $IPP_CONNECTION_INFO 2025-07-30 19:19:08.589 [IPEngine] WARNING | Not using CurveZMQ security 2025-07-30 19:19:08.609 [IPEngine] Loading connection info from $IPP_CONNECTION_INFO 2025-07-30 19:19:08.609 [IPEngine] WARNING | Not using CurveZMQ security 2025-07-30 19:19:08.842 [IPEngine.0] Registering with controller at tcp://127.0.0.1:34891 2025-07-30 19:19:08.842 [IPEngine.1] Registering with controller at tcp://127.0.0.1:34891 2025-07-30 19:19:08.842 [IPEngine.0] Requesting id: 0 2025-07-30 19:19:08.843 [IPEngine.1] Requesting id: 1 2025-07-30 19:19:08.844 [IPEngine.0.0] Shell_addrs: ['tcp://127.0.0.1:55003', 'tcp://127.0.0.1:39499', 'tcp://127.0.0.1:47313'] 2025-07-30 19:19:08.845 [IPEngine.0.0] Connecting shell to tcp://127.0.0.1:55003 2025-07-30 19:19:08.845 [IPEngine.0.0] Connecting shell to tcp://127.0.0.1:39499 2025-07-30 19:19:08.845 [IPEngine.0.0] Connecting shell to tcp://127.0.0.1:47313 2025-07-30 19:19:08.845 [IPEngine.0.0] Starting nanny 2025-07-30 19:19:08.846 [IPEngine.1.1] Shell_addrs: ['tcp://127.0.0.1:55003', 'tcp://127.0.0.1:39499', 'tcp://127.0.0.1:47381'] 2025-07-30 19:19:08.846 [IPEngine.1.1] Connecting shell to tcp://127.0.0.1:55003 2025-07-30 19:19:08.846 [IPEngine.1.1] Connecting shell to tcp://127.0.0.1:39499 2025-07-30 19:19:08.846 [IPEngine.1.1] Connecting shell to tcp://127.0.0.1:47381 2025-07-30 19:19:08.846 [IPEngine.1.1] Starting nanny 2025-07-30 19:19:09.269 [KernelNanny.0] Starting kernel nanny for engine 0, pid=4407, nanny pid=4418 2025-07-30 19:19:09.269 [KernelNanny.0] Nanny watching parent pid 4407. 2025-07-30 19:19:09.274 [KernelNanny.1] Starting kernel nanny for engine 1, pid=4408, nanny pid=4419 2025-07-30 19:19:09.275 [KernelNanny.1] Nanny watching parent pid 4408. 2025-07-30 19:19:09.333 [IPEngine.0.0] Loading IPython extension: storemagic 2025-07-30 19:19:09.334 [IPEngine.0.0] Running code in user namespace: from mpi4py import MPI mpi_rank = MPI.COMM_WORLD.Get_rank() mpi_size = MPI.COMM_WORLD.Get_size() 2025-07-30 19:19:09.335 [IPEngine.0.0] WARNING | debugpy_stream undefined, debugging will not be enabled 2025-07-30 19:19:09.337 [IPEngine.0.0] Starting to monitor the heartbeat signal from the hub every 3500 ms. 2025-07-30 19:19:09.337 [IPEngine.0.0] Completed registration with id 0 2025-07-30 19:19:09.339 [IPEngine.1.1] Loading IPython extension: storemagic 2025-07-30 19:19:09.340 [IPEngine.1.1] Running code in user namespace: from mpi4py import MPI mpi_rank = MPI.COMM_WORLD.Get_rank() mpi_size = MPI.COMM_WORLD.Get_size() 2025-07-30 19:19:09.341 [IPEngine.1.1] WARNING | debugpy_stream undefined, debugging will not be enabled 2025-07-30 19:19:09.343 [IPEngine.1.1] Starting to monitor the heartbeat signal from the hub every 3500 ms. 2025-07-30 19:19:09.343 [IPEngine.1.1] Completed registration with id 1 2025-07-30 19:19:13.834 [IPEngine.0.0] Handling execute_request: 1ca893d8-16070795d1968d9dead734bd_4354_1 2025-07-30 19:19:13.833 [IPEngine.1.1] Handling execute_request: 1ca893d8-16070795d1968d9dead734bd_4354_2 2025-07-30 19:19:15.585 [IPEngine.0.0] Handling execute_request: 1ca893d8-16070795d1968d9dead734bd_4354_3 2025-07-30 19:19:15.585 [IPEngine.1.1] Handling execute_request: 1ca893d8-16070795d1968d9dead734bd_4354_4 2025-07-30 19:19:16.210 [IPEngine.0.0] Handling execute_request: 1ca893d8-16070795d1968d9dead734bd_4354_5 2025-07-30 19:19:16.210 [IPEngine.1.1] Handling execute_request: 1ca893d8-16070795d1968d9dead734bd_4354_6 2025-07-30 19:19:16.221 [IPEngine.0.0] Handling execute_request: 1ca893d8-16070795d1968d9dead734bd_4354_7 2025-07-30 19:19:16.222 [IPEngine.1.1] Handling execute_request: 1ca893d8-16070795d1968d9dead734bd_4354_8 2025-07-30 19:19:16.235 [IPEngine.0.0] Handling execute_request: 1ca893d8-16070795d1968d9dead734bd_4354_9 2025-07-30 19:19:16.235 [IPEngine.1.1] Handling execute_request: 1ca893d8-16070795d1968d9dead734bd_4354_10 2025-07-30 19:19:17.170 [IPEngine.0.0] Handling execute_request: 1ca893d8-16070795d1968d9dead734bd_4354_11 2025-07-30 19:19:17.170 [IPEngine.1.1] Handling execute_request: 1ca893d8-16070795d1968d9dead734bd_4354_12 2025-07-30 19:19:17.182 [IPEngine.0.0] Handling execute_request: 1ca893d8-16070795d1968d9dead734bd_4354_13 2025-07-30 19:19:17.184 [IPEngine.1.1] Handling execute_request: 1ca893d8-16070795d1968d9dead734bd_4354_14
engine set stopped 1753899548: {'exit_code': 1, 'pid': 4400, 'identifier': 'ipengine-1753899547-3hrl-1753899548-4354'}